class Person { 
     private String name = "张三"; 
     private int age = 18;
     public void show() { 
         System.out.println("我叫" + name + ", 今年" + age + "岁"); 
     }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
}
class Test { 
     public static void main(String[] args) { 
         Person person = new Person(); 
         person.setAge(20);
         person.show(); 
     } 
}